JP4622913B2 - How to recognize the position of the recognition target - Google Patents

Description

  The present invention relates to a method for recognizing the position of a recognition target such as a jig nozzle.

2. Description of the Related Art Conventionally, an electronic component mounting apparatus including a mounting head for mounting an electronic component by horizontally moving between an electronic component supply unit provided on a base and a substrate is known. Further, the base is provided with a camera that images the electronic component sucked by the nozzle of the mounting head, and the position of the electronic component is recognized by analyzing the captured image. By controlling the position of the nozzle and the mounting height based on the recognized position of the electronic component, the electronic component is accurately mounted at a predetermined mounting position on the substrate with an appropriate pressure (see Patent Document 1).
JP 2000-36697 A

  Since such an electronic component mounting apparatus is provided with various drive mechanisms including a drive mechanism for horizontally moving the mounting head, heat generated from the drive mechanism generated in the process of continuously performing the mounting operation. In some cases, a displacement due to thermal deformation may occur between the mounting head and the base. For this reason, there is a deviation between the recognition origin of the camera and the position of the nozzle, which is the reference for the position recognition of the electronic component, and the position recognition result of the electronic component may include an error due to thermal deformation. As a result, the position of the nozzle and the mounting height at the time of mounting the electronic component are not appropriately controlled, leading to a decrease in mounting quality.

  In order to solve such problems, calibration is performed to measure the displacement of the camera recognition origin and the position of the jig nozzle mounted on the mounting head over time and correct the positional relationship between the camera recognition origin and the nozzle. However, if there is a problem such as foreign matter adhering to the jig nozzle, an abnormal value is included in the position recognition result of the jig nozzle, and appropriate calibration cannot be performed. As a result, the position and mounting height of the nozzle after calibration are not properly controlled, resulting in a decrease in mounting quality.

Accordingly, the present invention aims at providing a way to recognize the position of the recognition target without erroneous recognition due to the adhesion of foreign matter.

The invention according to claim 1 is a method for recognizing the position of a recognition object configured to be movable relative to the recognition means by the recognition means, wherein the recognition means recognizes the position of the recognition object over time. And recognizing the position difference between the recognition origin of the recognition means and the recognition target based on the difference between the position of the recognition target previously recognized in the recognition step and the position of the recognition target recognized later in the recognition step. A calculation step of calculating a correction value to be corrected, a correction value update step of updating a correction value calculated in the calculation step each time the position of the recognition target is recognized in the recognition step, and a correction value update step A step of setting an allowable value for allowing the updated correction value every time the correction value is updated, and determining whether the correction value calculated in the calculation step exceeds the allowable value A constant step, said the step of performing error processing when the correction value calculated in the calculating step is determined to exceed the allowable value, only contains the allowable value, every time updating of the correction value The correction value after the update is restored to the initial value, and gradually increases with time until the next update of the correction value .

  According to the present invention, since the correction value for correcting the positional deviation between the recognition means and the recognition target is updated with time, the position or height of the recognition target can be recognized without the influence of thermal deformation. In addition, since an allowable value that allows only positional deviation due to thermal deformation is set, and the positional deviation due to factors other than thermal deformation exceeds the allowable value, the correction value is not automatically updated. An abnormal value is not included in the position recognition result of the recognition target.

  FIG. 1 is a plan view of an electronic component mounting apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a control system of the electronic component mounting apparatus according to an embodiment of the present invention, and FIGS. FIG. 4 is an explanatory view showing a captured image of a jig nozzle in the electronic component mounting apparatus according to the embodiment of the present invention, and FIGS. 4A and 4B are jigs in the electronic component mounting apparatus according to the embodiment of the present invention. FIG. 5 is an explanatory diagram showing a captured image of an electronic component in the electronic component mounting apparatus according to the embodiment of the present invention, and FIG. 6 is a recognition method according to the embodiment of the present invention. FIG. 7 is an explanatory diagram showing the update status of the position and height correction value in the electronic component mounting apparatus according to the embodiment of the present invention, and FIG. 8 is a flowchart showing the recognition method according to the embodiment of the present invention. .

  First, the overall configuration of an electronic component mounting apparatus according to an embodiment of the present invention will be described. In FIG. 1, a substrate transport device 3 that transports a substrate 2 is arranged extending in the X direction on a base 1 that serves as a base of an electronic component mounting apparatus. The substrate transport device 3 has a function of clamping and fixing the substrate 2 and positions the substrate 2 transported in the X direction at a predetermined position. In the present invention, the transport direction of the substrate 2 is the X direction, and the direction perpendicular to the substrate 2 in the horizontal plane is the Y direction.

  A plurality of parts feeders 4 are arranged side by side on both sides in the Y direction of the substrate transfer device 3. The parts feeder 4 functions as an electronic component supply device, and sequentially supplies a plurality of electronic components accommodated therein to the supply port 5.

  A pair of Y tables 6 are disposed at both ends in the X direction of the base 1, and an X table 7 is constructed on the pair of Y tables 6. A mounting head 8 is mounted on the X table 7. The Y table 6 and the X table 7 are respectively provided with a Y-axis drive mechanism 6a and an X-axis drive mechanism 7a (see FIG. 2), and move the mounting head 8 horizontally relative to the base 1.

  In FIG. 2, a plurality of nozzle units 9 are mounted on the mounting head 8, and a nozzle 10 is mounted on the lower end of each nozzle unit 9. Each nozzle 10 is provided with a Z-axis drive mechanism 10a and a θ-axis drive mechanism 10b, respectively, and each nozzle 10 is configured to be movable up and down in the Z direction and rotatable in the θ direction (around the Z axis). Yes. In addition, each nozzle 10 is provided with an intake / exhaust mechanism 10c. When an electronic component is picked up, the inside of the nozzle 10 is sucked and held by suction, and when the electronic component is mounted, the nozzle 10 A so-called vacuum break is performed in which the electronic components are released by evacuating the inside 10. The Y-axis drive mechanism 6a and X-axis drive mechanism 7a, the Z-axis drive mechanism 10a, the θ-axis drive mechanism 10b, and the intake / exhaust mechanism 10c are connected to the control unit 11, and control commands transmitted from the control unit 11 are transmitted. Drive based on.

1 and 2, a camera 12 is disposed on the side of the mounting head 8. The camera 12 integrally moves with the mounting head 8 to move horizontally relative to the base 1 and functions as an imaging unit that performs imaging of a recognition target. A camera 13 is disposed between the substrate transfer device 3 and the parts feeder 4. The camera 13 is connected to the nozzle 1 from the supply port 5 of the parts feeder 4.
It functions as an imaging means for scanning the electronic component picked up by 0 from below. A line sensor 18 is disposed between the substrate transfer device 3 and the parts feeder 4. The line sensor 18 is a transmissive optical sensor, and functions as a detection unit that detects a light shielding length of a recognition target.

  In FIG. 2, the camera 12 is connected to a recognition unit 12 a, and the recognition unit 12 a is connected to the control unit 11, the calculation unit 14, and the storage unit 15. The recognition target image captured by the camera 12 is subjected to image processing by the recognition unit 12a, and the calculation unit 14 calculates the relative position between the center of the recognition target and the recognition origin of the camera 12. The storage unit 15 stores in advance distance data between the recognition origin of the camera 12 and the axis center of each nozzle 10, and the calculation unit 14 determines the axis center of any nozzle 10 of the mounting head 8 and the center of the recognition target. The relative position of is calculated. The control unit 11 controls the driving of the Y-axis drive mechanism 6a and the X-axis drive mechanism 7b based on the calculation result by the calculation unit 14, and thereby aligns the axis center of any nozzle 10 and the center of the recognition target. Is done. The recognition target by the camera 12 is an electronic component supplied to the supply port 5 of the parts feeder 4 at the time of pick-up, and a recognition mark for alignment provided at a predetermined location on the substrate 2 at the time of mounting. And a calibration recognition mark M (see FIG. 1) provided at a predetermined location on the base 1 at the time of calibration.

  In FIG. 2, the camera 13 is connected to a recognition unit 13 a, and the recognition unit 13 a is connected to the control unit 11, the calculation unit 14, and the storage unit 15. The recognition target image captured by the camera 13 is subjected to image processing by the recognition unit 13 a, and the calculation unit 14 calculates the horizontal positional relationship between the center of the recognition target and the recognition origin of the camera 13. Usually, the recognition target by the camera 13 is an electronic component sucked by the nozzle 10, and the mounting head 8 so that the axis center of the nozzle 10 sucking the electronic component to be recognized overlaps the recognition origin of the camera 13 on the captured image. Is positioned. Therefore, the relative position between the center of the electronic component calculated by the calculation unit 14 and the recognition origin of the camera 13 is a shift between the axis center of the nozzle 10 and the center of the electronic component, and the control unit 11 determines the calculation result by the calculation unit 14. Based on this, the drive of the Y-axis drive mechanism 6a and the X-axis drive mechanism 7b is controlled, and thereby the position of the electronic component attracted by the nozzle 10 is corrected.

  Note that when the position of the electronic component attracted by the nozzle 10 is recognized, the mounting head 8 needs to be positioned so that the axial center of the nozzle 10 and the recognition origin of the camera 13 overlap on the captured image. At least one of the plurality of nozzles 10 provided in the head 8 is replaced with a calibration jig nozzle 20, and the jig nozzle 20 is imaged by the camera 13 during calibration. The image of the jig nozzle 20 captured by the camera 13 is subjected to image processing by the recognition unit 13a, and the calculation unit 14 calculates the relative position between the center of the jig nozzle 20 and the recognition origin of the camera 13. The relative positional relationship between the center of the jig nozzle 20 and the recognition origin of the camera 13 is stored in the storage unit 15, and the control unit 11 controls the driving of the Y-axis drive mechanism 6a and the X-axis drive mechanism 7b based on this. The positional relationship between an arbitrary nozzle 10 that has attracted the electronic component and the recognition origin of the camera 13 is corrected.

  In FIG. 2, the line sensor 18 is connected to the control unit 11, the calculation unit 14, and the storage unit 15. The storage unit 15 stores the recognition origin in the line sensor 18. When the recognition target passes through the line sensor 18, a part of the sensor light is shielded by the recognition target, and the calculation unit 14 calculates the light shielding length from the recognition origin of the recognition target, that is, the vertical positional relationship with respect to the recognition origin of the recognition target. The Therefore, when the nozzle 10 in the state where the electronic component is sucked passes through the line sensor 18, the relative height with respect to the recognition origin at the lower end of the electronic component is calculated, and the nozzle 10 in the state where the electronic component is not picked up moves the line sensor 18. When passing, the relative height of the lower end of the nozzle 10, that is, the upper end of the electronic component with respect to the recognition origin is calculated. By calculating these differences, the height of the electronic component itself can be measured.

  Therefore, by calculating the relative height of the lower end of the nozzle 10 in a state where the electronic component is not picked up with respect to the recognition origin and storing it in the storage unit 15 in advance, the nozzle 10 in a state where the electronic component is picked up is then stored. When passing through the line sensor 18, the height of the electronic component itself can be measured. The storage unit 15 stores in advance the recognition origin of the line sensor 18 and the mounting height at the mounting location on the substrate 2, and the control unit 11 determines the Z-axis drive mechanism 10 a based on the calculation result by the calculation unit 14. By controlling the drive, the mounting height of the nozzle 10 is adjusted so that the electronic component is mounted on the mounting portion with an appropriate pressure.

  Further, when the electronic component is attracted in an abnormal posture such as a standing posture or an oblique posture, a numerical value higher than the height of the original electronic component is measured. Therefore, the height data of the electronic component is stored in the storage unit 15 in advance, and when the calculation result by the calculation unit 14 exceeds the height data value, the mounting operation is interrupted and the electronic component is removed. The error processing is performed to prevent the generation of defective substrates.

  An input unit 16 including a keyboard and a driver is connected to the control unit 11, and various data stored in advance in the storage unit 15 are input, or commands are directly input to the control unit 11. Further, an output unit 17 is connected to the control unit 11. The output unit 17 is provided with visual display means such as a CRT and a liquid crystal panel, and in addition to visually displaying the operation status in the electronic component mounting apparatus, is provided with a warning means, and an error is given to the operator when a malfunction occurs during operation of the apparatus. Communicate information.

  The calculation unit 14 performs various calculation processes in the electronic component mounting apparatus, and data necessary for the calculation process is stored in the storage unit 15 in advance. Furthermore, a control program is stored in the storage unit 15, and the control unit 11 controls the mounting operation in the electronic component mounting apparatus according to the control program.

  Next, a method for recognizing the center position of the recognition target will be described. 3 and 4 show captured images obtained by capturing the jig nozzle 20 with the camera 13. In FIG. 3A, a luminance detection window 22 is set in the imaging area 21 by the camera 13 to detect the luminance of the nozzle 20 and the peripheral portion 23 of the jig. In order to clarify the difference in luminance between the jig nozzle 20 and the peripheral portion 23, the jig nozzle 20 is set to have a higher reflectance than the peripheral portion 23, so that the image is captured at the time of imaging by the camera 13. The tool nozzle 20 and the peripheral part 23 are irradiated.

  The shape of a portion exceeding a certain luminance in the luminance detection window 22 is recognized, and the shape center on the picked-up image by the calculation unit 14 (the center of the circular jig nozzle 20 indicated by hatching in FIG. 3A). Is set as a temporary center 20b. If the jig nozzle 20 is in a normal reflection state, the shape of the jig nozzle 20 on the captured image matches the true shape, so the temporary center 20 b matches the true center of the jig nozzle 20. However, as shown in FIG. 4A, if a low-reflective foreign matter such as oil mist adheres to a part of the jig nozzle 20, for example, the lower left part, the brightness of that part is detected low. The temporary center 20b may be set at a position shifted to the upper right from the true center 20a. Further, as shown in FIG. 4B, if a highly reflective foreign material such as solder or dicing dust adheres to the upper right portion of the jig nozzle 20, the brightness of that portion is detected to be high. The center 20b may be set at a position shifted to the upper right from the true center 20a.

Therefore, in order to determine whether or not the temporary center 20b set based on the brightness exactly matches the true center 20a, the first window 22a and the second window 22b are set as the brightness detection window 22. The brightness of the jig nozzle 20 and the peripheral portion 23 is detected. In FIG. 3A, the first window 22a and the second window 22b are set as the luminance detection window 22 with the provisional center 20b of the jig nozzle 20 as a reference. The first window 22a is set to be located inside the jig nozzle 20 when the temporary center 20b coincides with the true center 20a. Here, the square first window 22a is the jig nozzle 20a. 20 is inscribed in the position. The second window 22b is set so as to be positioned outside the jig nozzle 20 when the temporary center 20b is the true center 20a, and is configured by a plurality of rectangles surrounding the jig nozzle 20 here. The rectangular side of each window is set at a position that circumscribes the jig nozzle 20. Since there are various types of jig nozzles 20 having different shapes and sizes, the first window 22a and the second window 22b corresponding to each jig nozzle are preset and stored in the storage unit 15.

  Since the first window 22a and the second window 22b are set on the basis of the temporary center 20b of the jig nozzle 20, the temporary center 20b is equal to the true center 20a as shown in FIG. If so, the first window 22a is inscribed in the jig nozzle 20 on the captured image, and the second window 22b is inscribed on the jig nozzle 20 on the captured image. In this case, the brightness of the relatively bright jig nozzle 20 is detected in the first window 22a, and the brightness of the peripheral portion 23 of the relatively dark jig nozzle 20 is detected in the second window 22b.

  On the other hand, as shown in FIG. 3B, if the temporary center 20b does not coincide with the true center 20a, the peripheral portion 23 is included in the first window 22a set with the temporary center 20b as a reference. Thus, the jig nozzle 20 is included in the second window 22b. Therefore, the average luminance in the first window 22a is detected to be smaller than the luminance when only the jig nozzle 20 is detected, and the average luminance in the second window 22b is that when only the peripheral portion 23 is detected. It is detected larger than the luminance.

  Here, assuming that the luminance of the jig nozzle 20 varies between the maximum value Amax and the minimum value Amin and the luminance of the peripheral portion 23 varies between the maximum value Bmax and the minimum value Bmin, it is shown in FIG. Thus, when the temporary center 20b coincides with the true center 20a, the relationship of Bmin ≦ average brightness in the second window 22b ≦ Bmax <Amin ≦ average brightness in the first window 22a ≦ Amax is established. To establish. Therefore, as shown in FIG. 3B, when the temporary center 20b does not coincide with the true center 20a, the average luminance in the first window 22a is smaller than Amin. Therefore, if the first threshold value is set smaller than Amin, the average luminance in the first window 22a will not exceed the first threshold value if the temporary center 20b does not coincide with the true center 20a. . On the other hand, regarding the relationship between the average brightness in the second window 22b and the second threshold, if the temporary center 20b does not coincide with the true center 20a, the average brightness in the second window 22b is It becomes larger than Bmax. Therefore, when the second threshold value is set to be larger than Bmax, the average luminance in the second window 22b exceeds the second threshold value when the temporary center 20b does not coincide with the true center 20a. . That is, as shown in FIG. 3A, when the temporary center 20b coincides with the true center 20a, Bmin ≦ average luminance in the second window 22b ≦ Bmax <second threshold <first The relationship of threshold value <Amin ≦ average luminance in the first window 22a ≦ Amax is established. Therefore, when the average luminance in the first window 22a exceeds the first threshold and the average luminance in the second window 22b does not exceed the second threshold, the temporary center 20b is the true center 20a. It can be determined that In addition, since the brightness | luminance detected by the 1st window 22a and the 2nd window 22b differs with the brightness | luminance set to the jig nozzle 20 or the peripheral part 23, it respond | corresponded to the reflectance of the jig nozzle 20 and the peripheral part 23. The first threshold value and the second threshold value are set in advance in terms of luminance and stored in the storage unit 15.

In addition to the jig nozzle 20 provided in the electronic component mounting apparatus described above as an object to be recognized, an electronic component sucked by the nozzle 10 and various recognition marks can be imaged to recognize the center positions thereof. . For example, when the recognition target is an electronic component, as shown in FIG. 5, the first window 31a is based on the temporary center 30b set based on the luminance of the electrode portion Pa.
And the second window 31 b is set on the luminance detection window 22. The first window 31a is set so as to be inscribed in the electrode part Pa of the electronic component P when the temporary center 30b of the electronic component P is a true center, and the second window 31b is formed on the electronic component P. Set to circumscribe. Thereby, by comparing the luminance in the first window 31a and the second window 31b with the first threshold value and the second threshold value, whether the temporary center 31b matches the true center of the electronic component P. A determination of whether or not can be made.

  The flowchart of FIG. 6 shows a method of recognizing the position of the center of the jig nozzle 20 in the electronic component mounting apparatus of the present embodiment in the order of steps. First, a step of setting a temporary center based on the luminance of the jig nozzle 20 is executed. First, the jig nozzle 20 is positioned in the imaging region 21 of the camera 13, and the luminance detection window 22 is set at a position surrounding the jig nozzle 20 (ST1, see FIG. 3A). Next, the jig nozzle 20 is imaged, and a temporary center 20b of the jig nozzle 20 is set (ST2).

  Next, a step of setting the first region with reference to the temporary center 20b of the jig nozzle 20 is executed. The first area is stored in the storage unit 15 as the first window 22a, and the first window 22a is set with reference to the temporary center 20b (ST3). Thereafter, the luminance in the first window 22a is detected, and the average luminance is measured by the calculation unit 14 (ST4).

  Next, a first determination step is performed to determine whether the average luminance in the first region exceeds the first threshold value. The average brightness in the first window 22a is compared with the first threshold value stored in the storage unit 15, and if it is determined that the first threshold value does not exceed the first threshold value, the temporary center 20b set in ST2 Is regarded as not coincident with the true center 20a, and error processing is performed (ST5). By the error processing, the temporary center 20b set in ST2 is discarded, and a new temporary center 20b is set. At this time, error information is transmitted to the operator by a warning means, and the operator inspects whether there is any abnormality in the jig nozzle 20 and performs cleaning such as removing the adhered foreign matter. Thereafter, the processes after ST2 are repeated, and the temporary center 20b of the jig nozzle 20 is newly set.

  On the other hand, when it is determined that the average luminance in the first window 22a exceeds the first threshold, a step of setting the second region is executed. The second area is stored in the storage unit 15 as the second window 22b, and the second window 22b is set with reference to the temporary center 20b (ST6). Thereafter, the luminance in the second window 22b is detected, and the average luminance is measured by the calculation unit 14 (ST7).

  Next, a second determination step is performed for determining whether the average luminance in the second region exceeds the first threshold value. The average brightness in the second window 22b is compared with the second threshold stored in the storage unit 15, and if it is determined that the second threshold is exceeded, the temporary center 20b set in ST2 Is regarded as not coincident with the true center 20a, and error processing is performed (ST8). On the other hand, if it is determined that the average luminance in the second window 22b does not exceed the second threshold value, the temporary center 20b set in ST2 is regarded as coincident with the true center 20a. (ST9). The true center position of the jig nozzle 20 recognized in this way is stored as center position data in the storage unit 15, and in the subsequent mounting operation, each nozzle 10 is stored based on the center position stored in the storage unit 15. Position control is performed.

The second window 22b set in ST7 is divided into a plurality of rectangular small windows and stored in the storage unit 15, and the step of comparing the average luminance for each small window with the second threshold is executed a plurality of times. It may be. In this case, error processing is performed when it is determined that the average luminance in at least one small window exceeds the second threshold. For example, as shown in FIG. 3B, when the temporary center 20b of the jig nozzle 20 is set at a position shifted from the true center 20a, the luminance of the jig nozzle 20 is reduced only by the small windows 22c and 22d. Therefore, the difference in luminance can be detected more clearly than in the case where the luminance is averaged over the entire second window 22b.

  As described above, in the recognition method of the present embodiment, the first region and the second region are set with reference to the temporary center of the recognition target such as an electronic component, a recognition mark, or a jig nozzle, and the inside of these regions is set. Compared with the average brightness of the image and a predetermined threshold, the temporary center is recognized as the true center only when a predetermined condition is satisfied, so that recognition based on the adhesion of foreign matter such as oil mist or dicing dust is recognized. The center position of the target is not erroneously recognized. As a result, position control in the electronic component mounting apparatus can be performed with high accuracy, leading to improvement in mounting quality.

  By the way, since the electronic component mounting apparatus is provided with various drive mechanisms including the Y-axis drive mechanism 6a and the X-axis drive mechanism 7a for horizontally moving the mounting head 8, the process of continuously performing the mounting operation. In this case, heat is generated from the drive mechanism, and a positional shift due to thermal deformation may occur between the mounting head 8 and the base 1. For this reason, the position and height of the electronic component recognized on the basis of the recognition origin of the camera 13 and the recognition origin of the line sensor 18 as a reference for the position recognition of the electronic component may include errors due to thermal deformation. . In order to solve such a problem, calibration is performed by measuring the positional deviation between the recognition origin and the jig nozzle 20 mounted on the mounting head 8 over time, and correcting the positional relationship between the recognition origin and each nozzle 10. Is called.

  The calibration includes a position calibration that corrects the positional deviation of the recognition origin of the camera 13 and the jig nozzle 20 in the horizontal direction, and a high correction that corrects the positional deviation of the recognition origin of the line sensor 18 and the jig nozzle 20 in the vertical direction. There is calibration. Regarding the position calibration, the jig nozzle 20 is imaged by the camera 13, a position correction value is calculated based on the deviation between the recognition origin and the center position of the jig nozzle 20, and the position of the electronic component recognized thereafter is obtained. Correction is performed with the position correction value taken into account. Regarding the height calibration, the jig nozzle 20 is detected by the line sensor 18, the height correction value is calculated based on the light shielding length by the jig nozzle 20, and the height of the electronic component measured thereafter is calculated. Perform corrections taking the height correction value into account.

  By performing these calibrations regularly or irregularly, position and height errors due to thermal deformation are eliminated. The position correction value and the height correction value are calculated by the calculation unit 14 and stored as correction data in the storage unit 15 while being updated for each calibration. The position and height correction are performed based on the correction data until the next calibration. Is done.

  Here, if foreign matter or the like adheres to the jig nozzle 20 between the previous calibration and the subsequent calibration, the center position and the light shielding length of the jig nozzle 20 are erroneously recognized in the subsequent calibration. In this case, if the position correction value or the height correction value is updated based on the center position or the light shielding length of the jig nozzle 20 that is erroneously recognized, an error is included in the position or height of the electronic component that is subsequently recognized. become. Therefore, if an allowable value that allows changes in the position correction value or height correction value due to thermal deformation is set in advance, and the position correction value or height correction value exceeds the allowable value, the calibration is performed between the previous and subsequent calibrations. It is determined that a foreign object or the like has adhered to the jig nozzle 20 and has been erroneously recognized, and error processing is performed.

  FIG. 7 schematically shows the relationship between the correction value and the allowable value. In the figure, the graph indicated by the solid line is the update status of the correction value (position correction value or height correction value), and calibration is executed at times t1, t2, t3, and t4, of which times t1, t2, and t4. The correction value is updated at. In the drawing, the graph indicated by the broken line indicates the update state of the allowable value, and is set to repeat the same pattern change every time the correction value is updated.

  The allowable value is an allowable change amount from the previous correction value when the correction value is updated, and is set to a value larger than the change amount due to thermal deformation. Here, the thermal deformation speed is set on the assumption that the thermal deformation increases in proportion to the passage of time, and the allowable value gradually increases with the passage of time from the time when the previous calibration is executed. Note that an initial value is set as an allowable value in consideration of an error margin due to resolution or the like in the camera 13 or the line sensor 18. Therefore, the allowable value is set by a linear function equation of “thermal deformation speed” × “elapsed time from the previous calibration execution” + “initial value”. In addition, the allowable value includes a correction value allowable upper limit that restricts the maximum correction value and a correction value allowable lower limit that restricts the minimum value, and the correction value allowable range is between the upper limit and the lower limit. . In addition, the maximum upper limit value and the maximum lower limit value are set for the allowable values set by the above linear function formula, and even if it takes a long time to perform the subsequent calibration, the allowable values are set. The value does not exceed the maximum upper limit value and the maximum lower limit value.

  The correction value calculated by the calibration is compared with the allowable value by the calculation unit 14, and if the correction value exceeds the allowable value, an error process is performed. That is, it is determined that foreign matter or the like has adhered to the jig nozzle 20 and has been erroneously recognized in the calibration, and the correction value of the storage unit 15 is not updated with the correction value, and the current correction value is continuously used. Further, the mounting operation is stopped by error processing, and an error warning is notified to the operator. The operator inspects and cleans the jig nozzle 20 to obtain a normal state in which foreign matters are excluded.

  As shown in FIG. 7, since the corrected value after calibration is within the allowable range at time t1, the correction value c1 stored in the storage unit 15 is updated to a new correction value c2. Similarly, at time t2, the correction value c2 is updated to a new correction value c3. However, since the corrected correction value c4 is outside the allowable correction value range at time t3, it is determined that some abnormality, for example, foreign matter is attached to the jig nozzle 20, and the correction value c4 is updated. The mounting operation using the previous correction value c3 is continued. Thereafter, if the correction value c5 when the calibration is performed again at the time t4 is within the allowable range, it is determined that the abnormality has been resolved, and the new correction value c5 is updated.

  Next, a method for updating the correction value during the mounting operation in the electronic component mounting apparatus will be described using an example of updating the height correction value for correcting the vertical positional relationship between the jig nozzle 20 and the line sensor 18. The position correction value for correcting the horizontal positional relationship between the jig nozzle 20 and the camera 13 is also updated in the same manner as the height correction value.

  Prior to starting the mounting operation, the allowable values stored in the storage unit 15 are initially set (ST1). In the stage where calibration has not yet been executed, the “elapsed time from the previous calibration execution” of the linear function equation for setting the allowable value is not set, so the elapsed time is set to infinity in the initial setting. Thereby, the allowable value is set to the maximum upper limit value and the maximum lower limit value.

When the mounting operation is started (ST2) and a predetermined time has elapsed, the nozzle 10 of the mounting head 8 is raised and the jig nozzle 20 is lowered and set to a predetermined height (ST3). In this state, the mounting head 8 is moved to the line sensor 18, the light shielding length by the jig nozzle 20 is calculated, and the relative height of the lower end of the jig nozzle 20 with respect to the recognition origin, that is, the height of the jig nozzle 20. Is measured (ST4). The height measurement (ST4) of the jig nozzle 20 is performed a plurality of times every predetermined time during the mounting operation, and calibration is executed based on the difference in the height measurement value of the jig nozzle 20. The calibration is executed when the difference between the height measurement value of the jig nozzle 20 measured earlier and the height measurement value measured later does not exceed the allowable value, and is stored in the storage unit 15. The height correction value is updated to a new height correction value after calibration (ST5). Thereafter, the mounting height at the time of mounting the nozzle 10 is managed based on the height correction value stored in the storage unit 15 until the next update. On the other hand, when the difference between the height measurement value of the jig nozzle 20 measured earlier and the height measurement value measured later exceeds the allowable value, error processing is performed (ST6). Due to the error processing, the height correction value is not updated, and the mounting height management using the height correction value before calibration is continued. Further, error information is transmitted to the operator by a warning means, and the operator inspects whether there is any abnormality in the jig nozzle 20, and performs cleaning such as removing the adhered foreign matter. Thereafter, the mounting operation is resumed.

  As described above, the position and height of the jig nozzle 20 of the mounting head 8 are recognized over time by the camera 13 and the line sensor 18 provided on the base 1 side, and the calibration of the position and height is appropriately executed. Accordingly, it is possible to prevent a decrease in positioning accuracy and mounting height accuracy due to displacement between the mounting head 8 and the base 1 due to thermal deformation. As a result, the position and mounting height of the electronic component when mounting the electronic component are appropriately controlled, and the mounting quality can be ensured by eliminating the influence of thermal deformation.

  In the present embodiment, the jig nozzle 20 is exemplified and described as the recognition target of the recognition means including the camera 13 and the line sensor 18, but the recognition target is not limited to the jig nozzle 20, and the nozzle 10 May be recognized directly.

  According to the present invention, since the correction value for correcting the positional deviation between the recognition means and the recognition target is updated with time, the position or height of the recognition target can be recognized without the influence of thermal deformation. In addition, since an allowable value that allows only positional deviation due to thermal deformation is set, and the positional deviation due to factors other than thermal deformation exceeds the allowable value, the correction value is not automatically updated. There is an advantage that an abnormal value is not included in the position recognition result of the recognition target, which is useful in the field of mounting electronic components that require high accuracy.

The top view of the electronic component mounting apparatus of one embodiment of this invention 1 is a configuration diagram of a control system of an electronic component mounting apparatus according to an embodiment of the present invention. (A), (b) Explanatory drawing which shows the picked-up image of the jig | tool nozzle in the electronic component mounting apparatus of one embodiment of this invention (A), (b) Explanatory drawing which shows the picked-up image of the jig | tool nozzle in the electronic component mounting apparatus of one embodiment of this invention Explanatory drawing which shows the picked-up image of the electronic component in the electronic component mounting apparatus of one embodiment of this invention The flowchart which shows the recognition method of one embodiment of this invention Explanatory drawing which shows the update condition of the correction value in the electronic component mounting apparatus of one embodiment of this invention The flowchart which shows the recognition method of one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Control part 13 Camera 14 Calculation part 15 Memory | storage part 18 Line sensor 20 Jig nozzle

Claims (1)

A method for recognizing a position of a recognition object configured to be movable relative to a recognition means by the recognition means,
A recognition step of recognizing the position of the recognition object over time by the recognition means;
A correction value for correcting a positional deviation between the recognition origin of the recognition means and the recognition target based on a difference between the position of the recognition target recognized in the recognition step and the position of the recognition target recognized later. A calculation process to calculate,
A correction value update step of updating a correction value calculated in the calculation step each time the position of the recognition target is recognized in the recognition step;
A step of setting an allowable value that allows the updated correction value every time the correction value is updated in the correction value updating step;
A determination step of determining whether or not the correction value calculated in the calculation step exceeds the allowable value;
A step of performing error processing when it is determined that the correction value calculated in the calculation step exceeds the allowable value;
Wherein the said tolerance, and wherein the correction value updated restored to the initial value to reference each time the update of the correction value, with time increasing until the next update of the correction value A method for recognizing the position of a recognition target .

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